This was the first time that anything this bizarre had been seen in the hallowed British Museum, which dates back to 250 years. Along its marbled galleries, between its grand columns and beneath its magnificent ceilings — normally oases of quiet, scholarly reflection — flakes of choking white material hung in the air before landing on staff frantically beavering away below. They looked like giant fluffy chicks, covered in it.

Although it seemed like a funny scene in a place with high culture, there was an extremely serious purpose behind the scenes. The museum was prepping for war in September 1939.

The doors had been closed to the public and thousands of precious exhibits — antiquities collected over centuries from all over the world and displayed for the edification of generations of visitors — were being packed into boxes, ready to be evacuated from the heart of London to places of safety, away from the danger of destruction by Luftwaffe bombers.

Cotton wool was wrapped round fragile items but for the rest there was cheaper kapok — tons of it — lighter, free floating and clinging. The Department of Ethnography packers used up all the kapok they could find, so the News Of The World was their last resort. This rag is racy and contains all the information you need to wrap bronzes or statuettes that were made by ancient civilisations.

A new invention was the key to simplifying the entire packing process. It was shocked at how many wooden boxes the museum would require when the plans were first drawn up. There was nowhere for them to be stored.

A manufacturer by the name of No-Nails had the solution with its revolutionary form of bulk packaging — hinged sheets of plywood folded into small cubes that could be opened out to full size when needed. This was the original flat-pack.

Pictured: Workers carry artworks to part of Piccadilly Circus underground station, to an area known as 'Aladdin's Cave' to store works from the Tate gallery

Pictured: Artists transport artworks from Piccadilly Circus Underground Station to an area called ‘Aladdin’s Cave’, where they store Tate works.

No-Nails boasted that its crates were so ‘extraordinarily simple’ to put together without tools that even ‘female labour’ could assemble them! Over 3,000 were ordered by No-Nails.

All over London, museums and galleries were making similar preparations to move their priceless treasures to safety — the National Gallery, the Tate, the Wallace Collection, the Victoria & Albert, the Natural History Museum. Buckingham Palace was also doing the same. The Houses of Parliament, Westminster Abbey, and others did the same.

Each participant was part of an incredible evacuation program that sent numerous pieces on high-risk journeys.

Although the scale of this operation is enormous, it went largely unnoticed due to the fact that it was conducted in complete secrecy so as not to attract thieves or hijackers.

The idea of Leonardo da Vinci’s Virgin Of The Rocks or Constable’s The Hay Wain being snatched was every curator’s nightmare. The convoys were accompanied to secret places by armoured guards.

In a new book, historian Caroline Shenton reveals the full story of this remarkable exodus for the first time as stately homes, tunnels, castles, quarries, prisons and caves became refuges for the nation’s treasures.

The Wallace Collection in the West End was bidding goodbye to its most famous exhibit, The Laughing Cavalier portrait (pictured) by Frans Hals, packed into a lorry accompanied by four guards armed with truncheons, on its way to Balls Park in Hertfordshire

The Wallace Collection of the West End bid farewell to The Laughing Cavalier Portrait (pictured by Frans Hals), which was loaded into a lorry accompanied with four guards armed in truncheons on its journey to Balls Park in Hertfordshire.

Nothing less than the preservation and promotion of our culture, history, and heritage was at stake. The surprising thing is the speed with which the danger was identified and that contingency planning was initiated.

In 1933, the Nazi party seized absolute power in Germany and began years of appeasement and dithering.

But not at the UK Government’s Office of Works. Its officials took seriously the warning from prime minister Stanley Baldwin that ‘the bomber will always get through’. Ahead of the game, they called in the heads of the major museums for an agenda-setting meeting on ‘precautions for the safe custody of national art treasures’.

A draft of a list of suitable, isolated country homes that were not obvious targets for bombing was created by the start of 1934.

Over the next five years, plans were refined and finalised, and by the beginning of 1939 — while Baldwin’s successor, Neville Chamberlain, was still striving for a peace deal with Hitler — a fleet of lorries was on permanent standby to hurry the treasures to safety at a moment’s notice.

This was led by the patrician boss at the National Gallery, Trafalgar Square. Kenneth Clark, a suave figure, is a key figure. He became Lord Clark of Civilisation after his groundbreaking television series on the arts.

Six brick sheds were built in Manod Mawr to house the art works during the Second World War

To house art work during World War II, six brick sheds were constructed in Manod Mawr.

The youthful Clark — only in his early 30s but already a man of stature in political and cultural circles — had learned all he needed to know about the threat from Hitler as his wife read Mein Kampf to him while he was shaving.

He was certain of what lay ahead and was determined for the protection and well-being of all his family, including Botticellis Rubenses Rembrandts Rembrandts Van Goghs, Rembrandts and Renoirs.

He began to rope in grand homes deep in the country as safety houses. Millionaires like the Astors or Rothschilds were also expected to be open the doors of their marquesses and Earls. Requisitions were mandatory for refuseniks.

Even resorting to blackmail to remind reluctant Old Fogeys that they could have evacuated children from East End dump on them if the Old Masters refused to house them. The majority of the people agreed.

But rather than have the National’s treasures scattered around the country, Clark’s preference was to keep as much of the collection as possible in one place. For this reason, Clark was drawn to the National Library of Wales (Aberystwyth) and Bangor University (both ideally located from London).

That was the place they were taken to on September 19, 1939, just a day before war was declared. After receiving the order, 700 paintings were loaded onto lorries and headed towards Euston station. Special trains were waiting at Euston station with security guards.

The British Museum was also snapping into action, with a procession of horse-drawn drays and handcarts shuttling boxes of ancient glass, Greek vases, gems and ceramics to their safe haven — the deep underground tunnels of the unused Aldwych Tube station.

They also took the Elgin Marbles friezes, as well as the recently discovered Saxon treasures in Sutton Hoo.

Given a rare glimpse inside, a journalist described his awe at seeing ‘the most amazing Aladdin’s Cave ever’ — Egyptian gods, Greek bronzes, Etruscan metalwork, statues of pharaohs and Caesar, Roman rings, and vases from ancient tombs.

‘Overhead,’ he wrote, ‘buses, taxis and Londoners were hurrying along without the slightest idea that beneath them was a gigantic Tutankhamun’s tomb.’

Aldwych was however a problem. It was lower than the Thames at high tide, and it was vulnerable to flooding or damp. It could not be used for manuscripts, fragile items and similar.

The 4th century Codex Sinaiticus, which contains the oldest complete New Testament text, the Lindisfarne Gospels and drawings by Raphael Michelangelo, Turner, was then taken to Aberystwyth’s watertight stacks.

The Wallace Collection at the West End bid farewell to The Laughing Cavalier Portrait by Frans Hals. The exhibit was packed in a lorry accompanied with four guards armed in truncheons on the way to Balls Park.

Also on the move were the Domesday Book, several Magna Cartas, Shakespeare’s will and Guy Fawkes’s confession, all prize historic possessions at the Public Record Office in Chancery Lane and now headed to Shepton Mallet prison in Somerset.

They arrived in their van early, and while waiting for them to arrive at the destination, the driver and his armed guards stopped by a café in the square. While they waited they had a cup of tea and accidentally left the doors open. Security is a problem!

Country house owners were required to adhere to strict guidelines when bringing in valuables. It was important to keep secrets. There was no need to brag about the temporary possessions of your neighbors.

Everyone who tried to hang a Van Dyck or place a Sevres porcelain container as a centerpiece on the dining room table with the intention of finding a Van Dyck, was in for disappointment. They were stacked high in the drawing area, in crates.

The items were also provided with staff to monitor them. It was not an easy arrangement. At Hellens in Herefordshire, where the Tate had deposited many of its pictures, the disgusted owner threw out one of the gallery’s men for getting drunk and brawling with the locals.

But at least the contents of London’s museums were safe, unlike the museums they had come from.

Bombs struck the Tate, and the walls of its building collapsed. The part of the Public Record Office where the Domesday Book had been stored was devastated; so too was the King’s Library at the British Museum. George III’s unique book collection was incinerated.

This proved that evacuation was possible, even though it came at a high price and required a lot of labor. However, many people were now more concerned about an invasion. Invasion.

With Hitler’s armies massed on the French coast after Dunkirk, the panicking trustees of the National Gallery pressed for its precious Old Masters to be urgently taken from their new home in Wales and shipped across the Atlantic to Canada for safety.

Clark, who was reluctant to accept the offer, was directed to send it to Winston Churchill. Clark refused to accept defeat. ‘Hide them in caves and cellars,’ he ordered, ‘but not one picture shall leave this island.’

This same attitude of defiance was shown by King, Queen, and their daughters. These were treasures of national importance, but they refused to leave.

If the princesses and their mother ever had to flee, Madresfield Court in the Malvern Hills — all 162 rooms, and a double moat — was on standby, with quick access down the Severn to the sea. It was given the code name ‘Harbour’.

In Yorkshire, there was ‘Security’, Newby Hall, if the Royal Family had to escape via Scotland. Two other boltholes were prepared in Shropshire — ‘Refuge’ (Pitchford Hall) and ‘Peaceful’ (Burwarton House). It was fortunate that none of them were needed.

The Crowns, Sceptres, and Orbs of Crown Jewels were just as delicate as the symbols of sovereignty. They are located in Tower of London. In the event of the country being conquered, they might be used to crown a Nazi puppet — the king’s abdicated brother, the former Edward VIII, was the likely candidate. It might be wise to take them to Canada.

This idea was rejected and royal regalia were kept in Windsor Castle. One day, their governess led Princesses Elizabeth (and Margaret) down to the vaults. She pointed out some rather drab looking leather hatboxes.

The lids were taken off and the Crown Jewels were glistened inside wrapped in newspaper.

The castle had other hidden places. The huge Cullinan diamond had been prised out of the sovereign’s sceptre, the Koh-i-Noor diamond from the Queen’s crown and, along with the Black Prince’s frog-sized ruby, wrapped in cotton wool and placed inside a glass jar. The Cullinan diamond was placed inside a Bath Oliver biscuit tartin.

A second piece of symbolism was also given a new home. It is a wooden Coronation Chair that dates back to 1300 and was used for crowning English monarchs.

The Scone, the Stone of Destiny, which traditionally sat underneath it, stayed, however — shored away behind planking and a pile of ancient lead coffins in a recess in the abbey crypt.

The location of the item was only identified by two sealed letters that were sent to Canada’s prime minister and to the Canadian High Commission. These letters will remain closed until needed.

Though he had lodged the National Gallery’s main works in Aberystwyth, the dynamic Clark was always on the lookout for somewhere safer.

A slate mine is located in Manod Mawr on the highest reaches in Snowdonia.

This mountain was nearly impossible to reach. Clark was determined to find local miners, who were able to blast out an even larger entrance. To house the artworks, six brick sheds were constructed.

It took the work nine months. In the summer 1941, Old Masters were loaded onto lorries and began to arrive in Aberystwyth. They arrived three times a day with half-ton containers, for five weeks, each, six days per week.

It was difficult to navigate the mountain roads. Clark enjoyed telling Clark about the difficulty of getting under a bridge outside Ffestiniog. Van Dyck, 12 feet tall Charles I on Horseback from Clark would never make it.

For several days, the road was dredged by navvies to increase its depth, but it was still only a half-inch from the original. Then, as Clark recalled, ‘the silence was broken as we all said in chorus, “Let the air out of the tyres”. It was done and grinding under, scraping over, the huge packing case passed through’.

The British Museum, which was looking for secure quarters at the time, chose a quarry located in the Mendip Hills. The Royal Enfield motor-cycle firm occupied a portion of it after hollowing out the site to make underground factories.

It was used to store furniture and textiles covered in cellophane, which were hung from railings. A visitor recalled that ‘shelves filled the space as far as the eye could see’.

One Cyril Gadd wrote graffiti on the wall. In Babylonian cuneiform script — what else would you expect from the British Museum’s Keeper of Egyptian and Assyrian Antiquities? — it read:

The year 1942 was the sixth year for George King of All Lands.

All the precious works, all of the artisans who worked in temples and palaces, were sent out that year.

To prevent them from being destroyed by fire or an attack by an evil foe

They were brought down into the cave below the ground, where they are safe and secure.

It is still there, says author Caroline Shenton, a reminder of the whole magnificent enterprise to save Britain’s most precious heirlooms from bombs and Nazis.

That project came to an end with Germany’s defeat and the treasures trickled back to their homes. The museums were opened again, and the contents of them restored. It was so secretive that few people knew that these treasures had disappeared.

  • NATIONAL Treasures by Caroline Shenton is published by John Murray, £16.99. Copyright © Caroline Shenton 2021. To order a copy for £15.95 (UK delivery free on orders over £20; offer valid until 25/12/21) go to or call 0203 176 2937.